Shaker conveyer



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SHAKER CONVEYER Filed Jan. 29, 1949 8 Sheets-Sheet 2 l l/ /l/ Irl/l Irll i Y 35 all NVENTOR Jelnh Ji Jy.

A TToR/vfx J. F. JOY

SHAKER coNvEYER Dec. 14, 954

Filed Jan. 29, 1949 Dec. 14, 1954 F Joy 2,696,906

SHAKER CONVEYER Filed Jan. 29. 1949 8 Sheets-Sheet 4 NVENTOR: Jsep/z JJyBf' Fm A TToRNE Y.

J. F. JOY

SHAKER CONVEYER Dec. 14, 1954 8 Sheets-Sheet 5 Filed Jan. 29, 1949NVENTOR:

- 755e hJJ BY: ATTORNEY.

Dec. 14, 1954 Filed Jan. 29. 1949 J. F. JOY

SHAKER CONVEYER 8 Sheets-Sheet 6 A T Tom/EY.

Dec. 14, 1954 J. F. JOY 2,696,906

SHAKER CONVEYER Filed Jan. 29, 1949 8 Sheets-Sheet 7 74 7g 4 62 i 58 ao/6 ff) /zoa Q00' o6 f /zzz Qz/ /fZ/z ABZ.

[NvENToR:

` ATTORNEY.

Dec. 14, 1954 J, F- JOY 2,696,906

SHAKER CONVEIYER Filed Jan. 29, 1 949 8 Sheets-Sheet 8 "MIN imm:FIL-7.15.

48 Al F1515! 330 328 324 Fris-,Za will 332 BYIV/Q A TTORNEY.

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SHAKER VCONVEYER turing Company, Pittsburgh;v Pa., a'rcorporatonf ofPennsylvaniaY Application 'January-29,- 1949,-Serial No. 73,625'

12 y Claims. (Cl.y 198-220).l

This inventionvrelates toy shaker conveyors,esp'eci'al1yk tohydraulicallydriven shaker conveyors.l

The rapid movement of materials has recently vbecome increasinglywimportantin industry. An example-.which may be cited isthe need forrapid movementV of coal` that goes with recently ,improved methods ofitearing .the coalloose from the face. Otherl examples in'industryxwillbeevident to those skilledvin theart.

Invthe case ofshaker'conveyors, the problem lis. tofkeep" the materialin motion; createdby ,the `fact that theconveyor. must' operate throughya return stroke during :.which'.

part of 'the'cycle no forward momentum is limparted to the materialbeing conveyed.Y It is highly vdesirable torgive- .the` .material ayhigh forward velocity during .the-working stroke in orderthataitfmayfemain lin inotion'duringzthey return stroke-of the conveyor,and itoikeep, the tune dura tion ofthe return stroke toa minimum becausethere:

turnstroke of the conveyor: involves lost time linzthe operating cycle.k

In attempting to solve the foregoing ,problems it is 'further. necessaryto bear'in mind .thatmany industrial appli-f cationsl will havelimitations onv the power avai1able,and` for that reason peak powerrequirements must be kept-- .at -a minimum.

It is--accordinglyan object yof this invention to provide amuch moreeiicient shaker conveyor than hasy heretofore been developed, -aconveyor having 1a long stroke which cany impart a high velocity .toathe transported material during lthe-workingory forward stroke,'suchthat the'fmaal terialcontinues it'sforwardy motion during ,the veryrapida return' stroke anduntil the conveyorv again movesforward. toimpart motion to the material. It is a further object oftliis inventionto provide -a hydraulic shaker conveyor with suitable controls, suchthatmaximum power requirements maybe keptwithinreasonableandfpracticable' bounds.

These and other objects are achieved in a hydraulicr shakerconveyorvprovidedwith' a reversiblehydraulic motor, to which fluid issupplied by a variable displacement pump.'- Regulation` of. thefpump, topreventexceeding a predetermined maximum load,` isv achieved by ,anaccumu- Another` accumulator '-in' the-'.uid supply line from thepumpserves asapressure uid reservoir, storing upf'iluid under pressure'whenthe lator` connected l'-to the fpump.

demand by the motor is less `thanpump-capa'city andde liveringA suchstored fluid when-demand is greaterv than pump capacity; thus the peakpower requirements' are di# minished substantially. i l

The reversible motor comprises a cylinderhaving-a pis-- ton reciprocabletherein',` and fluid supply ,thereto is et# fected vthrough a unique'reversingvalve which/'is itself controlled by the position of -'theconveyordrive-head.y

Figi4 lis a top' plan'view-fof `al shaker conveyor drive head 'andvassociated"mechanism made according'fto the-- invention, withthe-shaker p'ansl removed.

Fig;v 2"i' sa `vie`w in section -rthroughxthe longitudinal axis A of;the drive cylinder' comprising *th ghydraulic'motor.

Fig. 3 isl a` viewsomewhat sirrila -to"`Fig.j1 but orra` l `'away'and insection" to show-r' certain ldetails nircshown-in4 Fig:` 1.`

Fig1f4 'is a longitudinalsectionahyiew"througli'the' larger scale andwithparts" broke 2,696,906 Patented Dec. 14, 1954 "ice reversingvalveshowing-the valve in.' a neutral position.

The position` shown inFig. 4 is not anfoperating position.

Fig.- 5 yis another longitudinalsectional-'view of the ref versingvalvebut with the vplane* of the section beingper' pendicular to the planeofthe `section of Fig.f4 and showing the valvein an operating position.

Fig..6fis-a view similar toI Fig.,15, showing the yvalve in anoperatingposition in which fluidis admitted to one endthereof 'toshiftthe valveto another operating `position.

Figs.7 and 8 are-sectional Viewsvsimilar torFi'g. 5 but showing thevalve inother operating positions.

Fig. 9-is a view in sectionl on line 9`9 yof Fig'. 4.

Fig. 10 -is an enlarged detailview of a portion of the valve as showninv Fig.` 7, but -on a `scale approximately fourtim'es that of Fig.` 7.

Fig.v 1l is .a view inI sectionthrough thevariabledis-r placement pump.showing details thereof.k

Fig...12`is a view in-section substantially online 1212` Fig. l?, is' aview-'insection similar to Fig.- 1l but showing .the pump Vgears withltheir centers separated vsomewhat inordervto freduce lthe displacementof the pump.

Fig.. 14l is'a side elevationview of the discharge end of the conveyorshowing the material receiver ofV the conveyor in itsrelatio'ntotheterminal shaker' pari.y

Fig. l5 .isan elevation view as seenfrom'the'right end ofilFig.-v l4-(front or vdischarge end yofthe conveyor).

Fig. 16 isa view in section substantially on line 16'-16 of Fig.I 1showing vdetails of the pan carrying mechanism.

Fig. 17`s a view in section on line`17-17 of Fig. l.

Fig. 18 ris a viewin sectionon line 18-'18-ofFig. l.

Fig. 19 'is `an'enlarged view in section substantially on liney19-'-19"of` Fig. 18;`

Fig. 20 isa sectional view onahorizontal plane similar to' .that of Fig..19 but showing the rod connection between shaker pans ahead 'of lthoseparis carried rby the drive` Referring,.nowv in detail to'the drawings,especially Fig', l,iacro's'shead -2'is`mounte`d for reciprocation by..ahydraulic Huid-operated motor 4.` As is best seen in Fig. 2, u'idmotor 4comprises a cylinder 6T-and an operating piston 8. A piston rod 10extends through'suitable pack-V ing in the stung box12` and connectswith the crosshead 2 by means of a reduced diameter portion 14 at theendof piston4 "rode 10 and' a threadedV member '16 "oi'1` the end joflthe reducedv diameter portion-'14. y

At'fthe end 'of piston 8 opposite piston rod 10 there is mounteda guiderod 18 whichextends'through a stuffing box'20.- Guide rod 18 carriesapiston22, which operates in' a cylinder'24'." Cylinder 24 is preferablypressurized, i. es; charged -withnitrogen'ior air` and serves as a buierto "cushionf the stopping-'of `the main rdrive piston'8 at" v Y. `In'order` to permit the 'charging' of'cylinder `24 at'v opposite sides ofthe piston 22, cylinder 24iisl provided withv connections 26.` Theleft'end of cylinder24``is preferably'charged to ahigher pressure toassist" in* giving the-head the faster acceleration desired on thereturn stroke."

It will: vbe'-'underst;i`od byfthose skillediny'the art that"suitable/packing indicated generally at '28 will be usedinthef'stutnglboxes \12 "and -2l),l and also that suitable"sealin'g'ffmeans 'indicated'. generally* at y30 andAv 32 will be*provided for the'pistons Sand 22 respe'ctively.- The-de# tails fofthepackingand sealing means do not per se formapartjof'thisinvention,`andare, therefore',.not described herein.`v

A pressure-duid conduit 34 is connected to supply uid to 'one' 'end ofcyli'nder`4 through a connection 36.'v A

secondlpressure-uid conduit 38-l is connected tov supplyy 3 fluid underpressure to the opposite end of cylinder 4. It will be noted that pistonrod is larger in diameter than guide rod 18, so that for a given rate ofhydraulic fluid supply to the cylinder, piston 8 will move faster to theright, as seen in Fig. 2, than it will to the left.

It may be noted here that the crosshead 2 is connected by drive rodswith pan brackets 42, 44, 46 and 48. The details of these pan bracketsand their connections with the drive rods 40 will be disclosed below.

The supply of pressure fluid to the drive cylinder 4 is controlled by areversing valve indicated generally at 50. Fluid under pressure issupplied to reversing valve through a conduit 52, and fluid flows fromthe valve through two low pressure fluid connections 54 and 56.

Fluid under pressure is supplied to valve 50 through the aforesaid highpressure fluid conduit 52 by means of a variable displacement pump 58,having an inlet and an outlet 62 (Fig. ll). Pump 58 is preferablymounted in a fluid reservoir 64 with its intake passage 60 submerged orimmersed in hydraulic fluid. This mounting is effected by securing thepump casing to the cover 66 of the fluid reservoir by any suitable meanssuch as is shown in detail in Fig. ll. As can be seen in that ligure,the high pressure fluid conduit 52 terminates in a flanged connection68, which communicates directly with the pump outlet or discharge 62,and the pump is secured to the under side of the reservoir cover 66 bymeans of threaded members 70 passing through the flanged connection 68and engaging threaded openings in the pump casing. The flangedconnection 68 extends through an opening 72 in the reservoir cover 66and the top of the pump casing abuts directly against the lower face ofthe flanged connection 68. Suitable oil seal means 74 are provided toassure a fluid tight connection between the flanged connection 68 andthe pump outlet.

An accumulator of the enclosed bladder type, such as is disclosed inreissue Patent 23,437, is shown at 76. Accumulator 76 communicates withfluid conduit 52 by means of a conduit 78 which opens into the pumpdischarge at a point opposite the circle shown in dotted lines at 80(Fig. 11). This opening will not actually be visible in Figs. 11 and 13because of the nature of the section, but it is thought desirable toshow its location in relation to the rest of the parts of the pump. Asecond accumulator 82 of the same general type as the one shown at 76,is preferably connected to control the output of pump b81 in a mannerwhich will be described in greater detail e ow.

The two low pressure fluid connections 54 and 56 empty into a dischargeconduit 84 which conducts the exhaust fluid to a filter 86 through whichthe hydraulic fluid passes before it is recirculated through the system.It will be noted that for the sake of convenience, accumulators 76 and82 and their associated connections with the system are mounted in thereservoir 64. Any suitable motor 88, preferably an electric motor, maybe connected to drive the pump 58.

The reversing valve The reversing valve will now be described in detail,special reference being had to Figs. 4 to 10. A substantiallycylindrical shell 90 is provided with an internal bore 92 and aplurality of internal peripheral grooves 94, 96, 98, and 102. Theperipheral grooves communicate respectively with low pressure fluidconnection 54, pressure-fluid conduit 34, high pressure fluid connection52, pressure-fluid conduit 38, and low pressure fluid connection 56. Ifdesired, the valve could be made with the peripheral groovescommunicating-directly with the bore, but a preferred form ofconstruction is that shown,

in which a sleeve 104 snugly fits the bore 92 of the shell 90.

Sleeve 104 is provided with a plurality of sets of ports 106, 107, 108,and 112, which communicate respectively with peripheral grooves 94, 96,98, 100 and 102. Thus, in the preferred embodiment of the invention,communication between two or more peripheral grooves is by way of theinterior of sleeve 104 and the associated ports. The sleeve 104 isremovably secured in bore 92 by means of end caps 114 and 116. Thesecaps are held in place by any suitable means such as threaded members118 passing through the end caps and engaging the shell 90.

A hollow elongated main valve member 120 is reciprocably mounted in thesleeve 104. Main valve member 120 is provided with end pistons 122 and aplurality of port closers 124 and 125 between the end pistons 122. Inthe embodiment shown, the end pistons and port closers are ofsubstantially the same'external diameter as, and cooperate with, theinside diameter of the sleeve 104 to open and close certain of thesleeve ports. As is best seen in Fig. 4, port closers 124 and 125preferably have a dimension in the axial direction which is suflicientto close a port when the port closer is aligned therewith. It will benoted further that the main valve member 120 is itself provided withports 126, 128 and 130. When the valve is in the central position shownin Fig. 4 these ports are aligned with ports 106, 108 and 112respectively.

It was pointed out above that the main valve member 120 is hollow. Thishollow consists of an internal bore 132 in which a pilot valve memberindicated generally at 134 is mounted for reciprocation. The pilot valvemember consists of a hollow elongated element 136, of which the hollow138 is blocked substantially midway between its ends by a plug 140 heldin place by means of pins 142.

The elongated member is provided at its exterior with port closers 144,146 and 148. These port closers are in effect pistons which fill up theinternal bore 132 of the main valve member and thus serve to block fluidpassage in an axial direction through the main valve member. Inaddition, the elongated member is provided with end pistons 150 and 152which also have an external diameter such as to be reciprocable in andsubstantially block the internal bore 132 of the main valve member. Asis best seen in Fig. 10, the end pistons 150 and 152 are preferablysomewhat smaller than bore 132 to provide a clearance 153 and to permita throttling effect in operation. The hollow elongated element of thepilot valve member is further provided with ports or fluid passages 154and 156 at opposite sides of the plug 140 and with radial fluid passages158 and 160 at its ends.

An actuating rod 162 threadedly engages the end 164 of the pilot valvemember and a guide rod 166 threadedly engages the opposite end 168 ofthe pilot valve member. A suitable lock nut 170 engages the threadedportions of rods 162 and 166 to guard against loosening of the threadedconnections. As will be well understood by those skilled in the art, therods 162 and 166 pass through stuffing boxes 172, of which the packingand gland are secured between a flanged member 174 and a stuffing boxcap 176. The flanged member 174 engages an end of sleeve 104 and alsoserves to hold a seal 178 in place in anilillilar recess provided ineach of end caps 114 and The subject matter of the reversing valvedescribed in the foregoing is not claimed herein, but forms the basis ofa separate application, Serial No. 248,573, filed September 27, 1951,and assigned to the assignee of this invention.

The variable displacement pump Reference is now had to Figs. 1l, 12 and13 for a description in detail of the variable displacement pump. Thepump 58 has a pump casing 182 provided with a substantially circularrecess 184 at one end thereof and a substantially rectangular recess 186at its other end. A gear 188 is mounted for rotation in the recess 184and is keyed to motor shaft 190, which is rotatably supported inantifriction bearings 192.

Meshing with drive gear 188 is a follower gear 194 which is mounted forrotation on antifriction bearings 196 on a short shaft 198. Shaft 198 isin turn supported in a block 200 which has limited movement in therectangular recess 186 in a direction parallel to a line connecting theaxes of rotation of gears 188 and 194.

Gear casing 182 is provided at its right end with a bore 202 in which apiston rod 204 has a sliding fit. One end of rod 204 abuts against theright hand face of block 200, and at the other end of piston rod 204there is a piston 206 adapted to reciprocate in a cylinder 208; thecylinder is held in place by a threaded boss 210 secured in a threadedrecess in the gear casing. A cylinder head 212 threadedly engages thecylinder 208 at 214. Suitable sealing means 216 are provided between thecylinder and the cylinder head, and suitable piston packing 218 is heldin place by a washer 220, which itself is secured to the piston by athreaded member 222.

As can be seen in Figs. ll and 13, there is a clearance between theright end of cylinder 208 and the end of cylinder head 212. Thisclearance permits the interior The subject matter of the variabledisplacement pump referred to in the foregoingis not claimed herein, butformsth'e basis of a separate application, Serial No. 246,605,4iledSeptember: 14, 1951, and assignedto the assignee` of this invention.

The pilot valve actuating means The pilot valve member of the reversingvalve must be: actuated by some means in order to effect reversal ofzthefluid operated motor. The pilot Valve is actuated by reciprocation ofthe shaker conveyor drive head as willnow be described ingreater detail.

Pan bracket 42 (Figs. 1 and 16) carries an extension atits oneend, towhich there is secured a block 228;: The block 228 is hollow to permitthe passage there,- through of actuator rod extension v230. Extension230 is threadedly connected at its one end to a dog 232, which in turnisy threaded onto the end of actuator rod 162. Rod extension 230 carriesanother dog 234 which is adjustable alongthe rod in order to vary thelength of stroke of the shaker conveyor. A handle 231l (Fig. 23) ispreferably` attached to rod 239 in order that the pilot valve member maybe moved manually into a valve actuating positionvfrom the neutralposition shown in Fig. 4, just incase the apparatus should shut downwith the parts in neutral. y A

Alternative means for actuating the pilot valve may be provided ifdesired as `shown in Figs. 2l and 22. in this alternativeernbodimentvthev mechanism is` designed to permit` over-travel oftheactuating block, here shown as1actuating cam 228. ln this alternativeembodiment the pilot valve actuating rod 162' carries a pivoted dog 232.The, dog-232. is held in position to be engaged by thecam 228 by a coilspring 233 which holdsthe dog 232- against a stop `23S. The coil springis anchored at its:1 other endto aspringbracket 237.

The shakerconveyor material receiver Reference is now made to Figs. 14and15 for a detailed description of theA material receiver. of a shakerconveror made according to this invention isy preferably long in orderto permit the material being conveyedtoattain a high velocity ofmovement. lt should be rnotedthat the structure illustrated in Fig. 14appears end-for-end, as it were, with-respect to Fig. 1, the view ofFig. 14.. being what wouldbe seen by an observer looking towards thelongitudinal center line of Fig.; 1 fromV a point beyond the upper sideofthat ligure. A1 conveyor having suchga long stroke and dischargingitsrnaterialin a conventional manner will discharge the material-.overanarea having a substantial ylinear dimension-in the'direction ofmovement'of the shaker pans.

This fact-makes for dificulty in collectingthe materialV discharged fromtheconveyor; the material receiver of this inventiony overcomes thatdifficulty, permitting discharge of the-material at a ixed anddeterminable place.

Atsupport 238 isprovided in the vicinity of the terminalshaker pan 240in the pan line. The support consists-of-afbase member 242 in contactwith the ground, mine bottom, or-the like. Desirably the base member 242mayform awportion of the base of the structure illustrated in Fig. 1.Mounted on the base 242 are upright brackets `246 and 248, the brackets246 being disposed at one side of the pan line, and the brackets 248 atthe oppostexside of the pan line. Brackets 246 and 248 supportapair ofguides 250 and 252 respectively. Each ofiguides v25th and252-consistssimply of a pair of angle members 254and 256 mounted at opposite sidesof its associated upright bracket 246 or 248by any suitable meansas, forexample, by the nut and bolt assembly 258. The relative sizes of theangles 254and 256 are so chosen as to4 provide a horizontal spacetherebetween as is bestseen in, Fig.y 15.- A cross brace 26tlispreferably providedtol add, rigidity to the support 238.

A .pan carrierl 262 is provided with laterally extending membersV 264and k266engaging guides 250 and 252 respectively. A receiving. pan 268is secured to the pan carrier 262 by any suitable meansy as, forexample, by welding.. lfdesired, kthe -laterally extendingV guidemembers 264ar1d. 266 maybe secureddirectly to thepan` 2,68rinsteadlof-beingmounted ona pan .carrieres shown. In what follows it will' behelpful to bear in mind'that The stroke the termr.f'orward,'used withrespect l to al .shaker cona veyor, is essentially equivalent todischarge-.thus the forward end` ofashaker conveyor is the dischargaendthereof-whereas the. end1 of` thel conveyor referred'. toA as .therearwardend iis-the ,end at which the. tail'piece is located and awayfrom whichvmaterial is adapted to; be conveyed towards `the discharge.-end.

ln Fig. 14, the terminal shaker pan 240,.. (the pan at.

the discharge-endi of the conveyor) is shownin solid lines atvR, in yitsextreme. rearward position, andris shown indottedvlinesv at E in itsextreme forward position.r It

can be seen in Fig. 14 that the receiving pan 268, in its operatingposition, extends forward beyond; the forwardendot` the shaker pan whenthe shaker pan is lin; its-ex-l treme forward position,v andthereceivingpan268 [also extends rearward*` further thanA the.; extremerearward position of the forward end of the terminalshaker pan.

The under side of the terminal shaker pany isprovided with a pushermember; 270 at its extreme forwardlend',nv

preferably in the form of an angle member bent to conform to thetrough-like configurationfof'thepan.y Ascent,` be seen in the drawings,the, pusher member preferablyY just barely touches the` receiving, pan.

Provision is made, to allow the receiving pan to-be pushed back in thedirection toward the minefaceoutv of the way of such activity as may benecessary at the very end (the discharge end) of the pan line. To thatend the receiving panvis vslidably mountedpnits sup-. portas isdescribedin detail above, yand also means are, provided to lock the receivingPanl in operatingvposition,

For that purpose, the receiving pan and the pan car-v.

rier are notched orf recessed as shownv at 272`to,y receive a detent274,which may be movedl into-and out'ofr theV recessby ahandle 276. Morespecifically, the detent 274 may be securedl to handle 276 by a bolt27S. The

detent and handle assembly may be rotatably mounted` ina bearing 280,whichmay in turn be convenientlyy mounted on the cross brace 26th Panconnectors'and pan brackets 282, to the opposite ends of which therearebolted clamps.

284 and 286. Each-of these clamps includes an upper clamping element 288which is bent into ka V at its inner end to provide a pan-engaging; arm290, and which en,- gagesthedrive rod at its outer end. Clamping element288of clamp 284 cooperates withanother clamping element 292, and the twoelements are held together at` their outer end by a nut and boltassembly 294 to clamp.

the drive rod 4t) between them.`

Clamping element 28S of clamp-286 cooperates with another clampingelement 296. As in the Ycase of'clamp 284, a nut and bolt assembly2,94holds the two elements 288 and 296 tightly clamped about driverodv40.' The outer end of clamping element 296 extends laterally furtherthan the outer end of clamping elementv 292 in order that element 296may supportthe actuating block 228 which serves to reverse the pilotvalve as described above. As is more readily seen in Fig. 16, block 228is suspended from element 296 by means of a pair of hangers 298, whichcarry a clamp 300. Clamp 3MB-engages and holds the aforesaid block 228;

Fig. 17 shows details of the pan bracket 48. As can be seen by referenceto Fig. 17, pan bracketf48 consists of a cross member 302, to each endof which' a clamp 304 is secured as by welding. Each clamp 304 consistssimply of an open loop with a nut and bolt assembly 306 passing throughthe end. An upright arm 308y secured tothe upperface of eachV clamp 304engages one side of the trough-like shaker pan. The, pan is alsopreferably welded to bracket 48.

The details of pan bracket 46 are shown in Fig. 18, and the means bywhich bracket 46 is securedl for reciprocation by the drive head canbest be understood by a consideration of Fig. 19 as well as'Fig. 18. Asis best seen in Fig. 18, pan bracket 46 is preferably a single piecehaving a transverse portion 31()y bent in the vicinity of its outer ends`to form loops312, the ends of which in turn are bentupward and outward,toform.

pan-engaging arms 314.

Fig. 19 shows in detail the rod connection shown at 316 of Fig. 1. Ascan be seen in Fig. 19, drive rod 40 is a hollow member in the end ofwhich a stud 318 is secured, preferably by drilling a plurality ofperipherally spaced holes 320 and, with the stud 318 in place, fillingthe holes 320 with weld metal 322. The outer end of stud 318 may bethreaded as shown at 324, either before or after the stud is welded intothe end of rod 40.

The end of rod 40 forms a shoulder 326. The loop 312 of pan bracket 46slips over stud 318 and is clamped between shoulder 326 and the face ofa nut 328. Nut 328 is long enough to extend beyond the threaded end 324of the stud and is thus long enough to receive the threaded end 330 of astud 332 welded as explained above in the end of a pan drive rod 334.Pan bracket 48 is secured to the end of pan drive rod 334 as explainedabove.

The connections of adjacent pan drive rods in the direction of the mineface or other source of material to be conveyed, are shown in detail inFig. 20. It may be assumed that pan bracket 48 supports one end of ashaker pan which extends to the right as seen in Fig. 1, and to the leftas appears in Fig. 19. The other end of that pan is supported by a panbracket shown at 336 in Fig. 20. One end of pan drive rod 334 appears inFig. 19 and the other end thereof is shown in Fig. 20. As before, stud338 is welded in the end of drive rod 334. Stud 338 extends through theloop of pan bracket 336, which is substantially identical with panbracket 46 (Fig. 18), and the outer threaded end of stud 338 extendsbeyond pan bracket 336 and is engaged by a nut 348. Thus, the loop ofpan bracket 336 is clamped between shoulder 350 of rod 334 and face 352of nut 348. Nut 348 is welded to another pan drive rod 354 as shown at356, and a pan bracket 358 of the next adjacent pan is clamped aboutdrive rod 354 near its point of attachment to nut 348. Pan bracket 358is substantially identical to pan bracket 48 (Fig. 17).

Operation For a quick summary of the operation, reference should be madeto Fig. 24. The pump inlet is immersed in hydraulic fluid in thereservoir and discharges uid into the high pressure fluid connection 52.The reversing valve admits fluid first to one end of the drive motor 4and then to the other end of drive motor 4. Fluid discharged from thedrive motor passes through the reversing valve and returns to thereservoir by way of return line 84 (passing also through the filter 86shown in Fig. 3).

At the beginning and end of each stroke the output of pump 58 is greaterthan the demand for hydraulic uid by the Huid-operated motor, in thiscase the drive motor 4. When the duid-operated motor is moving atmaximum speed in either direction, the requirement for hydraulic fluidis greater than the capacity of the pump. When the demand for uid isless than pump capacity, the excess is stored in accumulator 76 and whenthe demand for uid is greater than pump capacity, accumulator 76discharges liuid into high pressure uid connection 52.

The operation of the Huid-operated motor and the reversing valve willnow be taken up in greater detail. Let it be assumed that thedescription of the operation begins with the main `valve member and thepilot valve member at the extreme right limits of travel (Fig. 5). Letit further be assumed that the drive head is nearing the end of itstravel toward the left as seen in Fig. 1. As it nears the end of itsleftward travel the block 228 engages dog 234 and pulls the pilot valvemember leftward into the operating position shown in Fig. 6. Thereupon,uid under high pressure is admitted from the high pressure iiuidconnection 52 into peripheral groove 98, whence it passes through ports108 in the sleeve 104, ports 128 in the main valve member, into theannular space between the main valve member and the pilot valve member,through ports 156 in the pilot valve member, along the right half of thehollow pilot valve member, and out through radial ports 160 in the end168 of the pilot valve member, whereupon uid at high pressure isadmitted to the right end of main valve member 120 and also to the rightend of the pilot valve member.

Also, with the parts in this position, the left end of the main valvemember is open to the low pressure fluid connection 54 by way of theannular passage between the main valve member and the pilot valvemember, ports 126 in the main valve member, ports 106 in the sleeve, andperipheral groove 94. With the high uid pressure at the right end of themain valve member and the pilot valve member, and low pressure at theleft end, the system is unbalanced so far as pressure is concerned. As aresult, the main valve member and pilot valve member move rapidly towardthe left into the position shown in Figs. 7 and 10. The pilotvalve'member will reach the end of its travel iirst, and as the mainvalve member nears the end of its travel, end piston 150 enters the endof bore 132. The clearance 153 provides a throttling effect whichcushions the stopping of the main valve member. if the main valve membershould stick momentarily, it will be started toward the leftmechanically by the pilot valve member, as shown in Fig. 8.

It should be remembered that meanwhile the shaker conveyor drive headhas reached the end of its stroke in a leftward direction. With thevalve parts occupying the relative positions shown in Fig. 7, highpressure liuid passes from the high pressure fluid connection 52 intoperipheral groove 98, through ports 108 in the sleeve, into the annularspace between the sleeve and the main valve member and between portclosers 124 and 125, through ports 107 in the sleeve, into annulargroove 96, and out through pressure uid conduit 34 to connection 36 atthe left end of motor 4. Fluid under high pressure is thereupon admittedto the left side of piston 8.

Meanwhile note that the right side of piston 8 is vented to the lowpressure of the reservoir by way of pressure fluid conduit 38,peripheral groove 100, ports in the sleeve, the annular space betweenthe sleeve and the main valve member and between port closer 125 andright end piston 122, ports 112, annular groove 102, low pressure fluidconnection 56 and exhaust conduit 84. This unbalance of pressures movesthe piston 8 rapidly to the right as seen in Fig. 2.

Inasmuch as the valve is symmetrical, the operation in the otherdirection is the same as the operation just described so the other halfof the cycle need not be described in detail, but will be understood bythose skilled in the art from the description given above.

As was explained earlier in this description, and as is best seen inFig. 2, piston rod 10 is larger in diameter than guide rod 18, whichwill result in a faster travel of the drive piston toward the right thantoward the left. With this arrangement the slow or working stroke willbe toward the left and the return or idler stroke will be toward theright, and the material transported will be moved leftward by the shakerconveyor.

Further attention is invited at this time to cylinder 24 (Fig. 2). Aswas explained above, cylinder 24 has reciprocating therein a piston 22,which is connected to guide rod 18 and moves against air or nitrogenunder pressure in cylinder 24 at both sides of the piston 22. Cylinder24 thus stores up energy which is put back into the system when piston30, and therefore, piston 22, have reached the end of a stroke and movein the other direction, serving to start movement immediately in saidother direction. Because of the higher pressure on the left side ofpiston 22, the acceleration will be greater on the return stroke. Inaddition, cylinder 24 serves as a shock absorber to slow down the shakerconveyor drive head near the end of each stroke by compressing the gasin that end of cylinder 24 toward which piston 22 happens to be moving.

It will of course be appreciated that in all normal operation of theinvention, fluid pressure moves the pilot valve in the same direction asit is moved by the block 228 cooperating with dog 232 or dog 234according to the direction in which the block happens to be moving. Toput it another way, assuming that block 228 engages dog 234 to initiatemovement of the pilot valve member leftward, as soon as the appropriatevalve passages are pro- `vided through the valve, iiuid pressurecontinues to move the pilot valve leftward and will ordinarily move thedog out of the way of the block 228.

As a safety measure, however, it may be desirable to use a cam and dogmechanism which permits over-travel of the cam. Such a mechanism isshown in Figs. 2l and 22 and was described above. In describing theoperation of a mechanism made according to the modification shown inFigs. 2l and 22, let it be assumed that the shaker head is moving towardthe right. Cam 228 engages the pivoted dog 232'. Pivoting of the dog isresisted by the coil spring 233 and the resistance of this spring issuicient to force movement of the pilot valve 112 and 13. As wasdescribed above,

`-.the resistauceof spring 233 as shown in Fig. 22. Cam 228' will ,bemade long enough to assure that it will not ride o'i vthe pivoted dog.in Vthe direction of over-travel.

The expedient shownin Figs. 2l and 22 alsoprevents damage'to themechanisminthe-eventof sticking of the Ypilot valve .member.for. .anyreason.

Regulation ofthe variabledisplacement pump will now be describedindetail. There are many industrial appli- .cations forshaker.conveyorsin which it will be necessary,

or at least kdesirableto.guard against over-loading of the pump .drivemotor. Such a safeguard is provided in the design of variabledisplacement pump shown in Figs. 11, the accumulator 82 `is yconnected.bymeans of aconduit226 to the cylinder i208. As fwillbennderstood/by..those skilled in the art, accumulator 82 will besolargek that the volume change effected inthe accumulator by the ktravelof piston '206 throughoutits limits .will .be negligible, andaccordingly, the pressure imposed uponpiston 206 will be substantiallyconstant. Under those circumstances, the resistance to relativedisplacement ofthe two pump gear centersimposed by thepistonandthe.accumulator will be substantially constant. This will result inproviding a substantially constant load for the drivemotor 8S.

As the pressure in the discharge or outlet 62 of the pump exceeds thepermissible maximum, gear 194.begins to moveto the right `against theresistance of theaccumulator, thus serving to unload the pump. Thisunloading of the pump by moving the centers of the gears apart permitsthe pump discharge pressure to drop slightly and as soon as thatpressure has again been reduced to a permissible value the two gearsreturn from the separated relationship shown in Fig. 13 to the fullymeshed relationship shown in Figs. ll and l2.

It will be noted that the piston rod 204 abuts against the right face ofblock 200 at some point above a line drawn through the two gear centersand extended toward the right. The purpose of this eccentric applicationof the resistance force is to overcome the unbalance caused lzaohigherpressure acting on the upper portion of block The operation of thematerial receiver will now be described in detail. Let it be assumedthat the receiving pan 268 occupies its' normal operating position asshown in Fig. I4. Let it further be assumed that the terminal shaker pan240 is in its extreme forward position F as shown in dotted lines. Asthe terminal conveyor pan is pulled back sharply on the return stroke,the material to be conveyed moves out of the end of the terminal paninto the receiving pan until the terminal pan reaches the most extremerearward position shown in full lines in Fig. 14. As the terminal panthen moves forward again on the vnext Work stroke, the scraper or pushermember 270 on the underside of the terminal pan engages the materiallying in the bottom of the receiving pan, and pushes it out and off theend of the receiving pan.

it wiil be understood by those skilled in the art that without amaterial receiver such as is disclosed herein, the transported materialwould be discharged from the conveyor 'over a linear dimensionsubstantially equal to the length of stroke of the conveyor. Where thislength of stroke is unusually long as in a drive head according to thisinvention-for example, 30 inches-this results in the transportedmaterial being deposited or discharged from the conveyor in such amanner as to make it dithcult to load the material thus discharged. Amaterial receiver such as is shown in this invention limits thedischarge of the transported material to the point at which thereceiving pan ends and thus makes loading of the discharged materialrelatively simple. This feature of the invention makes it easy for aconveyor of this type to discharge onto another conveyor at right anglesthereto with a. minimum of spillage.

With the conveyor temporarily stopped and the terminal shaker panwithdrawn to its most extreme rearward position, the receiving pan 263may be moved back out of the way by turning handle 276 to disengagedetent 274 from recess 272, whereupon pan 268 may be slid toward therear by means of laterally extending members 264 and 266 sliding inguides 250 and 252. The way is then clear for the movement of mine ycarsorv shuttle cars in front of the conveyor, or such other activity as maybe vneces- Vsa v It will be evident from the foregoing that thisinvention provides a much improved and-.more efficient shaker conveyorhaving the numerous advantages referred to herein.

Whlle there is in this application specically described one form whichthe invention may assume in practice, it will be understood that thisform of the same is shown for purposes of illustration, and that theinvention may be modified and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

l claim:

l. A` material receiver-fora shaker conveyor having a terminal-shakerpan, the material receiver comprising a support disposed in the vicinityof the terminal shaker pan, a pair of guides on the support at oppositesides of said pan, a receiving pan, means for supporting said receivingpan on said guides including members engaging the guides, the receivingpan being slidable back and forth along the axis of material movement,and means to lock the receiving pan against said back-and-forth sliding.

2. The combination of claim l, in which the receiving pan supportingmeans comprises a pan carrier to which said members engaging the guidesare secured.

3. In a shaker conveyor, a cylinder having a bore, a

piston reciprocable in said cylinder bore and kconnected to drive theshaker conveyor, a second cylinderhaving a bore discontinuous from saidirst cylinder bore, a piston reciprocable in said second cylinder bore,thetsecond cylinder being provided with a sealed charge of fluid underpressure, anda mechanical connection between the two pistons wherebycompression and expansion of the tluid in the second cylinderdecelerates and accelerates the shaker.

4. The combination of claim 3, in which the two cylinders are coaxialand adjacent, and in which the connection between the two pistonscomprises a single rod.

5. ln a shaker conveyor, cylinders separated by a stuifing box, a pistonmounted for reciprocation in one cylinder and connected to drive theshaker conveyor, a piston mounted for reciprocation inthe othercylinder, a rod connecting the two pistons and passing through thestuffing box, and a sealed charge of fluid under pressure in said othercylinder.

6. In a shaker conveyor, cylinders separated by a stuffing box, a pistonmounted for reciprocation in one cylinder and connected to drive theshaker conveyor, a second piston mounted for reciprocation in the othercylinder, a rod connecting the two pistons and passing through thestufng box, a sealed charge of uid under pressure in said other cylinderto which one face of the second piston is exposed, and another sealedcharge of fluid under pressure in said other cylinder to which theopposite face of the second piston is exposed.

7. A conveyor as in claim 6, in which one of the sealed charges is at asubstantially higher pressure than the other.

8. In a shaker conveyor, a cylinder, a piston reciprocable in thecylinder and connected to drive the shaker conveyor, a second cylinder,a piston reciprocable in the second cylinder, the second cylinder beingprovided with a sealed charge of uid under pressure acting on one faceof the piston operating therein and a second sealed charge of fluidunder pressure acting on the opposite face of the piston operatingtherein, and a mechanical connection between the two pistons.

9. in a shaker conveyor, a cylinder having a bore, a piston reciprocablein said cylinder bore, a piston rod connected with the piston andextending out through one end of the cylinder and connected to drive theshaker conveyor, a second cylinder having a bore, a piston reciprocablein the second cylinder bore, a piston rod connectingl the two pistonsand extending out through that end of the rst cylinder which is oppositethe tirst piston rod, the second piston rod having a smaller diameterthan the first, and a sealed charge of fluid under pressure in thesecond cylinder.

10. A conveyor as in claim 9, in which the sealed charge acts on oneface of the piston in the second cylinder, and there is another sealedcharge of fluid under pressure .in the second cylinder acting on theopposite face of the piston in the second cylinder.

1l. In a shaker conveyor, in combination, a reversible hydraulic motorhaving two working faces of diierent areas in order to provide thecharacteristic of moving faster in one direction than in the other for agiven fluid supply, a reversing valve, a pump, means including conduitmeans connecting the pump with the reversing valve and the reversingvalve with the motor, and means charged with gas under pressure andassociated with the hydraulic motor to accelerate vsaid motor at thebeginning of each stroke, said means having two chambers charged todifferent pressures such that the acceleration is greater in onedirection than in the other direction, and the elects of greaterhydraulic motor speed and greater acceleration being additive.

12. A shaker conveyor comprising: a reversible hydraulic motor of thepiston-and-cylinder type, having a drive rod of a given cross-sectionalarea secured to the piston and extending out through one end of thecylinder, and a guide rod of a lesser cross-sectional area secured tothe piston and extending out through the opposite end of the cylinder,whereby fluid supplied at a given rate to the first-named end of thecylinder will move the piston faster than uid supplied at the same rateto the secondnamed end of the cylinder; a reversing valve; a fluidsupply pump; means connecting the valve with the two named ends of thecylinder; means connecting the pump with the valve; means to drive thepump; and means charged with gas under pressure and associated with thehydraulic motor to accelerate said motor at the beginning of eachstroke, said means having two chambers charged to different pressuressuch that the'acceleration is greater in one direction than in the otherdirection, and the effects of greater hydraulic motor speed and greateracceleration being additive.

References Cited in the ile of this patent 5 Number Number UNITED STATESPATENTS Name Date Deane Oct. 31, 1876 Coombs Aug. 28, 1877 Chapin Oct.22, 1878 Sargent July 24, 1917 Malinowsky June 17, 1919 Linkowski May22, 1923 St. Clair June 21, 1927 Sklenar Nov. 12, 1929 Nyborg et al.July 14, 1931 Smith May 23, 1933 Moore Apr. 9, 1935 Rankin June 18, 1940Hagenbook Apr. 22, 1941 Ernst Oct. 20, 1942 Rapp Nov. 2, 1943 HagenbookFeb. 29, 1944 Sloane Nov. 23, 1948 Grosser Dec. 28, 1948 Jacobsen Jan.4, 1949 Conklin Sept. 13, 1949 Rutherford Mar. 21, 1950 Aldridge Jan.20, 1953 FOREIGN PATENTS Country Date Germany Jan. 29, 1930 GreatBritain Dec. 18, 1940

